Covaxin Is Safe, Enhanced Immune Response in Phase 1 Trial: Lancet

These are interim results and they do not determine the long-term safety outcomes or efficacy of the vaccine.

Covaxin Is Safe, Enhanced Immune Response in Phase 1 Trial: Lancet

Covaxin, India’s first indigenous COVID vaccine candidate, led to ‘tolerable safety outcomes’ and ‘enhanced immune responses’ in the phase 1 trial, revealed an interim report published in The Lancet on Thursday, 21 January.

The double-blind randomised controlled study assessed the safety and immunogenicity of the vaccine candidate at 11 hospitals across India. 375 healthy adults aged 18-55 years were enrolled.

The findings from the trial are important in the context of growing vaccine hesitancy after India launched its vaccination drive on 16 January, especially towards Covaxin - since it is still undergoing phase 3 trials in larger groups.

According to the peer-reviewed phase 1 study, the vaccine induced binding and neutralising antibody responses that were similar to those induced by other inactivated vaccine candidates.


“However, to the best of our knowledge, ours is the only reported inactivated COVID-19 vaccine candidate inducing cell-mediated responses and humoral neutralising responses,” the study noted.

The most common adverse event was pain at the injection site, followed by headache, fatigue, and fever. All were mild or moderate, and more frequent after the first dose. The only serious adverse event of viral pneumonities which was reported, has been deemed unrelated to the vaccine, said the findings.

Importantly, these are interim results and they do not indicate the long-term safety outcomes or antibody responses. They also cannot help assess the efficacy of the vaccine, warranting and necessitating phase 3 trials.

On Sunday, January 3, COVAXIN became India's first indigenously produced vaccine against the novel coronavirus to get 'restricted approval 'emergency approval for public health interest.' The vaccine has been developed by pharma major Bharat Biotech in collaboration with Indian Council of Medical Research (ICMR) and National Institute of Virology (NIV).

But this approval raised many questions due to a lack of sufficient safety or efficacy data from large-scale trials. Dr Anant Bhan, Adjunct Professor & Researcher in Bioethics at Mangaluru’s Yenepoya University, told FIT in an earlier interview,

“An efficacy of a vaccine can only be determined after it has gone through large scale phase III trials, which are still ongoing.”.
Dr Anant Bhan

Phase 3 trials on over 25,000 participants are underway, the recruitment for which was completed only in early January this year.

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